The present invention relates to an automatic web splicing system provided to a machine for manufacturing cigarette rods or filter rods, and more specifically, to an automatic splicing system suitable for a web which is thin and the tensile strength of which is relatively low like a web used for wrapping paper of the cigarette rods.
An automatic web splicing system is indispensable for enabling the continuous operation of a machine for manufacturing cigarette rods or filter rods. The automatic splicing system of this kind automatically changes over a web feed from an active roll to a standby roll when the residual amount of the active roll becomes low in the process of feeding the web from the active roll toward the manufacturing machine. For the purpose of the changeover, the automatic splicing system comprises a reservoir device.
More specifically, the reservoir device has a reservoir disposed downstream of a main feed roller feeding the web toward the manufacturing machine, the reservoir being capable of reserving the web. Prior to the foregoing changeover of the rolls, the reservoir device causes the web from the active roll to be fed at a higher speed than the running speed of the web in the manufacturing machine in cooperation with the main feed roller, and reserves the web by the length required therein. For this reason, when the web feed is changed over from the active roll to the standby roll, it is possible to splice the web of the active roll to that of the standby roll, that is, to change over from the active roll to the standby roll, with the active roll stopped from rotating while the web which has been reserved in the reservoir is being supplied to the manufacturing machine.
During the web feed from the active roll, the active roll is subjected to predetermined braking force. Since the active roll is rotated against the braking force as the main feed roller rotates, the web is stably fed from the active roll toward the manufacturing machine.
In order to improve the production capacity of the manufacturing machine, it is required to increase the speed of operation of the manufacturing machine itself, that is, the rotational speed of the main feed roller. To this end, it is necessary to increase not only the braking force to be applied to the active roll but also the speed of operation of the automatic splicing system, that is, the speed in reserving the web into the reservoir.
However, the web used for manufacturing cigarette rods is thin and also relatively low in the tensile strength thereof. On this account, an increase in the braking force applied to the active roll tends to cause rupture of the web during the web feed. Accordingly, there is a limit to increase the speed of the web feed, or the rotational speed of the main feed roller.
In the automatic splicing system, the higher the speed of the web feed (web-consuming speed in the manufacturing machine) is made, the more the web-reserving speed and the web reserve amount in the reservoir increase. Consequently, it is extremely difficult to orderly reserve the web in the reservoir by a significant amount, and then to smoothly supply the reserved web from the reservoir toward the manufacturing machine.
When the web is intertangled in the reservoir during the web storing operation into the reservoir, there occurs a tear in a side edge of the web, which makes the web rupture easily. After the changeover of the above-mentioned rolls is completed, and the web reserved in the reservoir is exhausted, the web is fed from the standby roll. At this time, the standby roll is in a halt state while being subjected to the braking force. Therefore, at the start of the web feed from the standby roll, the standby roll is abruptly rotated by the pulling force due to the delivery of the web. Thus, the web of the standby roll is given a considerable shock, which easily causes rupture of the web.
An object of the present invention is to provide an automatic web splicing system capable of feeding a web at a high speed without causing rupture of the web, and of making a stable changeover from the active roll to the standby roll.
An automatic splicing system according to the present invention comprises a web feed source including a pair of web rolls, an active path for guiding a web drawn out from one of the web rolls to a main feed path as active web, and a standby path for causing the web drawn out from the other web roll to stand by as standby web.
Moreover, the automatic splicing system comprises a main feed roller disposed in the main feed path and feeding the active web toward a consumption device, residual amount-detecting means for detecting a residual amount of the web of said one web roll, a sub-feed roller disposed in the standby path and feeding the standby web from the other web roll along the standby path when the residual amount of the web reaches a predetermined value or less, speed-detecting means for detecting feed speed of the standby web, and splicing means splicing the standby web to the active web in a splicing position when the feed speed of the standby web matches that of the active web, and simultaneously severing the active web in a position upstream from the splicing position while severing the standby web in a position downstream from the splicing position, thus changing over the web to be fed from the main feed roller from the active web to the standby web.
The web feed source includes a pair of spindles on which the respective web rolls are mounted, driving means capable of rotating the web rolls individually by means of the respective spindles thereof, a pair of buffer chambers located in the active path and the standby path, respectively, the buffer chambers being capable of sucking and drawing the webs fed along the respective paths so as to make the webs into a U-shape, a pair of draw-detecting means for detecting amounts of the webs drawn into the respective buffer chambers, controlling means for controlling a rotational speed of each of the web rolls by means of the driving means so that the detected draw-in amount of the corresponding web may be maintained within a predetermined range.
According to the above automatic splicing system, while the active web is fed from one of the web rolls toward the consumption device, the rotational speed of the web roll is controlled so as to keep the draw-in amount of the active web to be drawn into the buffer chamber within the predetermined range. Accordingly, the active web stably runs on the path between the web roll and the main feed roller without slacking or suffering an excessive tension.
Thereafter, when the residual amount of the web roll reaches the predetermined value or less, the other web roll is rotated by the driving means therefor, and simultaneously the sub-feed roller is also rotated as the feed of the active web is continued. Thus, the feed of the standby web from the other web roll is started. When the feed speed of the standby web matches that of the active web, the splicing means splices the standby web to the active web, and the web to be fed by the main feed roller is changed over from the active web to the standby web.
In the above-described web-changeover process, the rotational speed of the other web roll is controlled to maintain the draw-in amount of the standby web drawn into the buffer chamber within the predetermined range, as in the case of the active web. The standby web also neither slacks nor suffers the excessive tension, so that the splicing operation of the active web and the standby web can be stably performed.
When the active web and the standby web are spliced together as described above, both the webs are in a running state, and therefore, tension proof strength required of these webs is small. Accordingly, even if the feed speed of the active web is high, the automatic web splicing operation can be securely carried out.
In addition, since the automatic web splicing operation does not require a reservoir device, there is no possibility of a trouble attributable to use of the reservoir device.
Preferably, the web feed source may further include exchanging means for interchanging positions of the foregoing web rolls. Specifically, the exchanging means comprises a roll mount provided with the spindles at both ends thereof and rotatably supported in a center position between the spindles and a motor for rotating the roll mount around the center position thereof.
In this case, when the automatic web splicing operation is accomplished, the roll mount is rotated, and the web rolls are interchanged with respect to their positions. In other words, the web roll of the standby web is moved to the position where the web roll of the active web has been located, and then the standby web is fed toward the consumption device as an active web.
Moreover, the web feed source may further include shifting means for shifting the buffer chambers individually along with the respective web rolls when the web rolls are interchanged. In this case, even if the web roll of the standby web is moved, the stable feed of the standby web can be secured.
Specifically, each of the buffer chambers is capable of reciprocating motion in a direction taken along a moving direction of the corresponding web roll and in a direction orthogonal to the moving direction thereof, that is, frontward and backward thereof. In this case, since the buffer chambers are shifted without interfering with each other, the web rolls can be smoothly interchanged.
On the other hand, the web feed source may further include pushing means for pushing the webs toward the respective buffer chambers. In this case, after the used web roll is replaced with a new one, the pushing means helps a standby web drawn out from the new web roll to be automatically drawn into the corresponding buffer chamber.
Moreover, the automatic splicing system may include a reservoir device for the active web. The reservoir device is disposed in the main feed path, that is, the reservoir is located downstream from the main feed roller, and temporarily reserves the active web prior to the automatic web splicing operation.
Such a reservoir device allows the feed speed of the active and standby webs to decrease at the time of the automatic web splicing operation, thereby making it possible to perform the automatic web splicing operation more stably. Additionally, the utilization of the reservoir does not stop the feed of the active web, so that a reserve amount of the active web required in the reservoir of the reservoir device, is small.
Furthermore, the consumption device is a machine for manufacturing cigarette rods, filter rods or filter cigarettes. The automatic splicing system feeds the webs for cigarette rods, filter rods or filter cigarettes toward the machine, and carries out the automatic splice thereof.